The goal of any technical process is to produce a product that has specific properties. In the ideal case, the product hereby has exactly the specific properties. In practice, the properties of the product can, however, deviate from the desired properties by specific tolerance bands. Depending on the situation of the individual case, the permissible tolerance bands can be determined here by the later use and/or further processing of the product as such by—more or less arbitrary—stipulations of the customer for the product or by law.
There can be multifarious causes of the deviation of the actual properties (actual variables) from the desired properties (setpoint variables). For example, the production process can be subjected to disturbances. Again, the deviation of the actual variables from the setpoint variables can possibly be ascribed to inhomogeneous material properties or interventions by an automation device in the production process.
The general statements above are also valid specifically for the machining of a rolling stock in a rolling mill. The machining corresponds in general here to a rolling of the rolling stock, that is to say a reduction in the cross section thereof in a rolling stand. In exceptional cases, however, other types of treatment also come into consideration, for example, heat treatment in a cooling line that is arranged downstream of a rolling train.
Examples of desired properties of a rolling stock are                in the case of a strip-shaped rolling stock, its thickness, to a lesser extent its width and the flatness of the rolling stock,        in the case of a bar-shaped rolling stock, its height and width, in some cases also the ratio of height to width (height and width are orientated orthogonal to one another in this case),        the tension prevailing in the rolling stock and the microstructural properties, independently of the cross section of the rolling stock. In particular the microstructure determines the later processing possibilities, for example the deep-drawing property of sheet metal. The microstructure is particularly strongly influenced by the heat treatment in the cooling line.        
Rolling mills of the prior art have a basic automation and technical controls. The basic automation comprises, in particular, individual controls, for example for a rotational speed of a drive motor of a rolling stand, or a lift height of a loop lifter by means of which the tension is set to a desired tension. The technical controls comprise superimposed controllers. They determine the desired values for the basic automation. Examples are the determination of a desired roll gap, a desired rolling force, a desired rolling speed or a time profile of the amount of coolant which is to be applied at a specific location on the rolling stock. In the prior art, both the controllers of the basic automation and the controllers of the technical control respectively have a typical controller for the respective control task, for example a P controller, a PI controller, a PD controller, a PT1 controller, etc. Furthermore, a respective controller characteristic is determined for each controller. In the case of a PI controller, for example, the controller characteristic comprises its proportional gain and its integration time constant.
In the prior art, the type of controller and the controller characteristic are determined if possible in such a way that the respective controller controls as stably and accurately as possible. In particular, the aim is to use the technical controls to regulate and control the process in such a way that the quality-relevant variables are adhered to as well as possible. The aim here is for disruptions in the process behavior brought about by guiding interventions and disturbances, and the fluctuations that are caused thereby in the material properties after the rolling mill has been run through, to be kept as small as possible. However, in many cases it is not possible to determine the controller characteristic thus. For example, this can be caused by the fact that the instantaneously respectively optimum controller characteristic depends on the respective operating state of the rolling mill, for example on the instantaneous state of the rolling stock to be machined, or on an instantaneous speed at which the rolling stock is running through the rolling mill.
It is known in the prior art for controller parameters to be determined in rolling mills dynamically and as a function of state and for the controller parameters respectively determined to be prescribed to the controller. For example, the roll gap of a rolling stand can be controlled by a roll gap controller, the controller being parameterized as a function of the material properties (composition and cross section), as well as the temperature and the rolling stock speed.
Furthermore, it is known to determine controller parameters dynamically and adapt them appropriately to the controller. Reference may be made to DE 103 27 663 A1, by way of example.